At the beginning of the funeral, the Fox Lake Police Department awarded Lt. Gliniewicz the committee's Medal of Honor. Gliniewicz also served in the Armed forces.

During the visitation Monday morning, Gliniewicz's wife, Mel, received hugs from a line of officers and other mourners beside a stage displaying a dress uniform and a folded American flag. Gliniewicz was the father of four sons.

Gliniewicz, a 30-year police veteran only a month from retirement, was shot Tuesday morning while pursuing the men he spotted on his way to work. Gliniewicz told dispatchers the three ran into a swampy area, and he requested a second unit. Gliniewicz, 52, reported the chase to dispatchers before communication was lost. Backup officers arriving minutes later found him shot.

Gliniewicz was popular in suburban Chicago and was nicknamed "G.I. Joe." He coached teenage trainees in the police Explorer program, a program for those considering a career in law enforcement.

"He was very proud of the Explorer group that he championed for 30 years," Mayor Donny Schmit, a close friend, told CBS News. "Just a good guy, a wonderful sense of humor. He's going to be dearly missed."

During the funeral, Gliniewicz was described as a father to those who went through the Explorer program. Around 70 percent of those who went through the program went on to police or military work.

"... he was a dad to about a thousand others," said Retired Fox Lake Police Chief Mike Behan.

Begnaud reports that the 18 mile procession slowed in front of the Fox Lake Police Department.

"He was the policeman's policeman," Schmit said, struggling to keep his emotions at bay. "He did everything by the book, and I don't know how anyone could've done this to him."

A young fellow police officer, Nick Garcia, was one of many who eulogized Gliniewicz, affectionately called "Joe." He described Joe as an awesome dad, a mentor to police officers and a friend to many.

George Filenko of the Lake County Major Crimes Task Force holds a news conference at a vigil for slain Fox Lake Police Lieutenant Charles Joseph Gliniewicz in Fox Lake, Illinois, United States, September 2, 2015.

REUTERS/Jim Young

FBI technicians are piecing together surveillance videos to help in the search.

Authorities investigating the slaying say they've recovered a new piece of "significant" evidence from the crime scene.

Evidence technicians returning to the scene of Tuesday's shooting in the village of Fox Lake made the discovery Friday afternoon, said Lake County Sheriff's Office detective Christopher Covelli.

He refused to reveal what it was, citing the ongoing investigation.

"They've been going back to the scene on a daily basis with a fresh set of eyes," he told The Associated Press Saturday.

Late last week, investigators announced they had new video that possibly shows the suspects. They said the video is being analyzed, according to Lake County Major Crimes Task Force Cmdr. George Filenko, the lead investigator on the case.

"I think we are optimistic about all these videos right now," said Filenko during a press conference Friday.

During the press conference on Friday, Filenko said the officer's weapon has been recovered at the scene. The new video being analyzed comes from businesses and residents.

The village has named a new interim chief and deputy chief to head the grieving department that has been without a permanent chief since last month.

Behan's retirement came days after he was put on paid administrative leave during an investigation of an altercation between an officer and a man arrested last year. Since then, a Fox Lake police lieutenant has been leading the department. The new interim chief is Lake County Sheriff's Office Deputy Chief Michael Keller and the interim deputy chief is Sgt. Scot Kurek of the sheriff's department.

Though officials said the interim appointments had nothing to do with the ongoing investigation into the slaying of Gliniewicz, they said that given all the uncertainty surrounding the investigation into the former chief and the officers' grief over the death of a beloved colleague, it made sense to bring in new leaders.

"Given Tuesday morning's tragedy, they wanted to bring in seasoned leadership," said Dave Bayless, a spokesman for the village.

Fox Lake Mayor Donny Schmit agreed.

"As we mourn the loss of Lieutenant Gliniewicz, we need to enable the members of the police department time to recover and heal from the impact of the tragedy that felled their comrade and friend," he said in a statement. "We are also mindful of our obligation to provide our police officers with strong leadership so that the department can continue to function at an optimal level and provide critical services to our community even during this very difficult time."